„How Cannabis Causes Paranoia“ - Why This Study Is Deeply Flawed

A new study has just been published directly linking the use of cannabis to paranoia. Although significant, you should take these results with a healthy degree of skepticism, as there is a pretty big flaw.

You may have come across articles in The Guardian and BBC reporting about the findings of a study in which scientists apparently have found a link between cannabis and paranoia. The study, published in Oxford Journals this month, outlines how they have proven that cannabis can cause paranoid thoughts, and media outlets were eager to jump on the „Cannabis doubles risk of paranoia“-bandwagon. However, those findings are based on a flawed study.

A paranoia study on paranoid people

To conduct the experiment, academics from the University of Oxford recruited 121 volunteers who had previously used cannabis at least once, and had reported having paranoid thoughts within the last month. The volunteers were split up into 2 groups. One was given a 1.5mg injection of pure THC, whilst the other was given a placebo. The participants were then subjected to a number of tests to establish paranoid thoughts.

It was found that 50% of the THC group displayed signs of paranoia, whereas only 30% of the placebo group did. Those who took the THC also showed signs of anxiety, lowered mood and negative thoughts – all of which cannabis is regularly used to treat! A significant finding, some would say.

THC isn’t equal cannabis

It’s quite obvious, but most news outlets don’t care to mentioned it: THC isn’t equal to cannabis. Of course, THC is the best known compound within cannabis, but the plant contains a wide range of other cannabinoids - more than 80 - that influence the effect. For example, cannabidiol (CBD) is the second most abundant cannabinoid after THC, and what this study has failed to take into account is that CBD has been shown to regulate and dampen the effects of THC, including its ability to induce feelings of paranoia and anxiety. Another example of a cannabinoid that reduces feelings of paranoia is CBN (cannabinol), which has been shown to have a calming and relaxing effect. It is the combination of various cannabinoids at different levels that allow different strains of cannabis to be anything from uplifting and energizing, to calming and relaxing. After all - who goes around injecting pure THC into their bloodstream?

The second flaw concerns the selection of participants. All participants have reported having paranoid thoughts before, which obviously skews the direction of the outcome. If this study show anything at all, it is that people with a pre-existing paranoia issues tend to experience more paranoia after the injection of pure THC. But this finding doesn’t translate into „cannabis doubles risk of paranoia“.